Neurobiology. In the article “β subunits influence the biophysical and pharmacological differences between P- and Q-type calcium currents expressed in a mammalian cell line” by Herman Moreno, Bernado Rudy, and Rodolfo Llinás, which appeared in number 25, December 9, 1997, of Proc. Natl. Acad. Sci. USA 94, 14042–14047, the following correction should be noted. Due to an editorial change at PNAS, the meaning of the last sentence on page 14046 was altered. The sentence originally read as follows: On the other hand, this structure does not reproduce the pharmacological properties of either P or Q channel exactly, as the ID₅₀ to sFTX and ω-Aga IVA for P-type channels is lower than for the α1A, α2δ, βIb channels in HEK cells.